In modern elevator installations, the tendency is to reduce as much as possible the ground surface and the height occupied by the installation. One of the solutions found to reach this aim is to eliminate the machine room which, till now, was located either at the top or at the bottom of the hoistway or else in a lateral local of the hoistway, and to secure the control equipment, for instance the controller, on a wall of the hoistway. Nowadays, it is well known to manufacture machines and controllers having a small thickness, which can then be secured in the space comprised between the hoistway and the car.
In the elevators of this kind, a balustrade is generally provided on the roof of the car, in a position somewhat offset from the edge of the roof to prevent any risk of falling into the hoistway when the roof is not at the level of the controller.
When a technician had to intervene on the controller or on the machine to effect maintenance or reparation operations, he has to climb onto the roof, to control the motion of the car and to stop it when the controller is within easy reach. Since the controller protrudes with respect to the wall of the hoistway, it arrives sufficiently near to the car to eliminate any risk of falling in the hoistway.
However, the technician had to work through the bars of the balustrade, or over the balustrade, i.e. at distance from the controller. In this position, certain working operations become rapidly uncomfortable and tiring. Furthermore, since the balustrade must be made of steel to guarantee sufficient resistance, its interposition between the technician and the controller increases the risk of electrical shock during operations made on electrical components.